In recent years new, obscure or poorly known dermatological disorders have been described and better defined, with emphasis on clinical, histopathological and etiopathogenetic features. Familiarity with these new, emerging or revisited clinical entities is fundamental, and recognizing them with their differential diagnosis has important implications in clinical practice for better patient management.

Part 1. ENTITIES WITHOUT OR LITTLE SYSTEMIC IMPLICATIONS.- 1.Autoinflammatory Keratinization Diseases.- 2.Adult Mucinoses: New And Revisited Variants.- 3.Pediatric Cutaneous Mucinoses.- 4.Circumscribed Palmoplantar Hypokeratosis.- 5.Necrotizing Infundibular Crystalline Folliculitis And Necrotizing Eosinophilic Folliculitis.- 6.Annular Erythema: New And Revisited Variants.- 7.Frontal Fibrosing Alopecia.- 8.Terra Firma-Forme Dermatosis And Dermatosis Neglecta.- 9.Papular Epidermal Nevus With "Skyline" Basal Cell Layer (PENS).- 10.Grover Disease.- 11.The Spectrum Of Acquired Elastolytic Disorders.- 12.Post Irradiation Pseudo-Sclerodermatous Panniculitis.- 13.Linear Focal Elastosis And Pxe-Like Fibroelastolytic And Elastotic Papulosis Disorders.- 14. Rare Variants Of Keratosis Pilaris.- 15.Cutaneous Collagenous Vasculopathy.- 16.Acquired Hyperpigmentation Disorders Of Uncertain Etiology.- 17. Eruptive pseudoangiomatosis, eruptive hypomelanosis and paraviral exanthems.- 18.Morbihan Disease.- Part 2.ENTITIES WITH SYSTEMIC IMPLICATIONS.- 19.Aquagenic Keratoderma.- 20.New Or Unusual Skin Manifestations In Monoclonal Gammopathies.- 21.Lipophagic/Lipoatrophic Panniculitis: A Th1 Mediated Autoimmune Disorder Of The Subcutaneous Fat.- 22.Covid19-Related Cutaneous Manifestations.- 23.PAPA, PASH, PAPASH, PsAPASH and PASS: autoinflammatory syndromes of Hidradenitis Suppurativa.- 24.Re-Emerging And New Skin Infections.- 25.Skin Adverse Reactions From New Cancer Immunotherapy.- 26.Newly Recognized Variants Of Neutrophilic Dermatosis.- 27.Cutaneous Reactive Angiomatoses.- 28.Skin Manifestations of Immunoglobulin G4-Related Disease.- 29.Necrolytic Acral Erythema (NAE).- 30.Reactive Granulomatous Dermatitis (Interstitial granulomatous dermatitis, palisaded neutrophilic and granulomatous dermatitis, and variants).- 31.Chronic Atypical Neutrophilic Dermatosis With Lipodystrophy And Elevated Temperature (CANDLE) and Proteasome Associated Autoinflammatory Syndrome (PRAAS).- 32.Spiny Keratoderma.- 33.Cocaine-Levamisole-Induced Vasculitis/Vasculopathy Syndrome.- 34.Lymphocytic Thrombophilic Arteritis (Macular Lymphocytic Arteritis).- 35.Dermal Hyperneury.- 36.Emergent cutaneous T-cell pseudolymphomas.